diff --git a/sys/modules/rpi_ft5406/Makefile b/sys/modules/rpi_ft5406/Makefile
index 2360ceda44a..3a1bbf5762a 100644
--- a/sys/modules/rpi_ft5406/Makefile
+++ b/sys/modules/rpi_ft5406/Makefile
@@ -5,6 +5,6 @@
 KMOD=	rpi_ft5406
 SRCS=	bcm2835_ft5406.c
 
-SRCS+= bus_if.h device_if.h ofw_bus_if.h
+SRCS+= bus_if.h device_if.h mbox_if.h ofw_bus_if.h
 
 .include <bsd.kmod.mk>